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SeaBat Case Stories
Icelandic Killer Wales
Observing Interactions between Predators
and Prey: the Case of Herring-eating Killer
Whales
By Filipa Samarra - [email protected]
Situation
Killer whales, as top predators can have important impacts
on marine food webs, but understanding these impacts, particularly in the face of changing environmental conditions
requires an understanding of the adaptability of their feeding behavior. Icelandic killer whales are thought to feed
predominantly on herring, a fish that dramatically changes
Photo by Miguel Neves
its behavior throughout the year, depending on whether it is
spawning, in the summer, or overwintering, in the winter.
The aim of this project is to study if and how the feeding
behavior of Icelandic killer whales changes at differen times
of the year to adapt to their prey behavior.
SeaBat Case Stories
Photo by Sara Tavares
Challenge
Equipment
To achieve this we study how wild killer whales interact
with herring using a SeaBat 7128 Multibeam sonar in
winter and summer. Underwater visibility in these waters is
very poor and the sonar is the perfect tool to allow us to see
what is happening underwater. This study will allow us to
assess what factors influence and potentially constrain the
feeding behavior of killer whales and predict their
adaptability to changes in the marine ecosystem.
We use the SeaBat 7128 with a sound velocity profiler from
a small (5.7m) zodiac mounted on a pole. In the summer we
also use a separate small (8m) cabined boat to deploy the
sonar, using the same pole system. The advantage of using
the SeaBat is the fact that it can be deployed from our vessel, so it’s relatively portable, and crucially it’s wide horizontal beam is essential for our research as the whales feed in
groups. Therefore, we need a wide horizontal beam to be
able to capture the whole group feeding event, which is
what we are interested in studying.
Killer wales seen in the SeaBat 7128 wedge interface
Watch the video of the wedge at www.teledyne-reson.com/killerwales
SeaBat Case Stories
Photo by Sara Tavares
Location
We conduct this study in two locations in Iceland at different times of the year. In Feb/March in Grundarfjordur (West)
and in July in Vestmannaeyjar (Southwest). The map below
shows the location of these sites.
This project is funded by the National Geographic Global
Exploration Fund – Northern Europe, the Icelandic Research
Fund (i. Rannsóknasjóður) and supported by Teledyne
RESON.
To read more about the project visit: www.icelandic-orcas.com
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